1. Field of the Invention
The present invention relates to a copying machine and particularly, to a premaintenance system therefor.
2. Description of the Prior Art
An electrophotographic copying machine widely used as a copying machine is comprised of a variety of parts such as photoconductor drum, developer means, various chargers and the like. In such a copying machine, each part does not necessarily have the duration of life same to those of other parts since use conditions of them are different from each other.
In other words, each part has a proper duration of life due to the condition under which it is used.
In a conventional electrophotographic copying machine, there is provided a premaintenance function for enabling to request maintenance for each of important parts thereof when exchange of it is decided to be necessary. According to this function, when the number of copies has attained to a predetermined number, an instruction such as "MAINTENANCE CALL" is displayed on an operation panel thereof. The user, when he recognized the instruction, calls a service man. If the service man receives the call, he will exchange at least one of parts to new one before it is worn out. This guarantees a long life of the copying machine without any trouble.
Since each part to be premaintained has a proper duration of life as mentioned above, the premaintenance cycle for the maintenance request function, namely the exchange cycle should be determined corresponding to each of parts to be maintained.
However, in a conventional maintenance system, only one exchange cycle is predetermined so as to be the greatest common measure among various duration of lives of individual parts since the maintenance system becomes complicated if respective exchange cycles of parts are to be set independently.
However, it is to be noted that the actual duration of life of each part is greatly affected by the environment in which the copying machine is settled and the manner of use. In other words, the exchange cycle as G. C. M. should be naturally be altered according to use condition under which the copying machine is used.
However, in the conventional copying machine, the exchange cycle is predetermined regardless to the use condition. Further, though it can be altered after the settlement of the machine, it is not so easy to set a suitable exchange cycle in place of the predetermined one.
In another conventional copying machine, a plurality of checking items are provided and individual items are checked separately (See JP-A No. 60-76765).
Further, there has been proposed a copying machine having a plurality of counters for counting the number of copies and numbers of use times of individual parts to be checked.
Furthermore, there has been known a copying machine having counters for counting respective numbers of copies corresponding to respective sizes of copy papers (See JP-B No. 57-59548) or a copying machine having a counter for counting the number of miss copies other than a copy counter of normal copies (See JP-A Nos. 58-219570 or 58-219571).
However, in these copying machines, each of premaintenance cycles is determined beforehand.